Fixing MKTurbo Car
 

Hey all,

Picked up a pristine NA8 with 55k miles on it last month that was sold due to "poor running, inability to idle, poor driveability" with the MKTurbo kit. Seller was frustrated with it, and just wanted it gone. Figured I'd start a thread here outlining what I've done to it, and let you guys pick it apart and give me some tips as well. This is my first "non-factory" turbo car, but I've got about 4 miatas worth of maintenance experience.

The Build: MKTurbo Complete Package with MS3Pro

What I've done so far:
1) The Idle VE values were about 1/2 what they should have been. Car would not idle, assuming this means the previous tuner just tried to autotune it above a certain RPM and gave up on idle? After fixing the VE values (I read a TON on how to tune idle), and setting up the other startup values, it starts up after a few cranks even when cold, and idles just fine. I've had it die once or twice off of a hard accel back down to idle, but I'll keep working at it.
2) MAP sensor was tee'd off of the BOV ref port, and the Boost Gauge. Took the tee off for the BOV ref, left the tee on for the interior boost gauge. Seems to have a more stable reading now.
3) Currently replacing the abused K&N filter (not pictured). It had collapsed from what I assume to be clogging.
4) Car got to about 245deg F when I was driving it a few weeks ago testing the tuning, hard pulls with the AC on in stop and go traffic, 100 degrees outside. Drained the coolant (it was dark green), refilled with about 80/20 distilled mix and antifreeze using vac fill tool. Has not gotten over 220 after that. The car has an LRB undertray installed. I have the side panels as well, but they still need to be trimmed for the intercooler piping.
5) Still working on the catch can setup. Reading a TON of conflicting threads on this. Can someone point me to a good one for a boosted car? I'm hearing much about "porting" the valve cover.
6) The O-ring sealing the piston on the knockoff BOV was knocked down onto the shaft. This was creating a significant boost leak, and I'm assuming was why the PO was complaining about "late boost". Car builds from 2500 to 4k rpm up to 11psi easily now.
7) The wastegate actuator is hitting the hood bracing. I can't seem to see an easy way to fix this, anyone have experience on this particular clocking of the turbo with this kit? Keeping AC (Texas) and PS.

https://cimg9.ibsrv.net/gimg/www.mia...f0c4b02cf3.jpg

my wastegate was also rubbing on hood. I bought one of these

https://www.ebay.com/itm/382997451079

https://i.ebayimg.com/images/g/6QEAA...TC/s-l1600.jpg

Gives a bit of clearance.

Your catch can is correct for a VTA setup. I'd personally like to plumb it back into the intake for a street car, it puts vacuum on the crank case which has numerous benefits, and burns the vapors rather than putting them into the engine bay. If you use a quality catch can and your engine is healthy, you shouldn't fill them up.

As for boost, my fav fix is an external gate welded to the turbine housing. If you have anyone local who's a good welder, it's fairly simply. It also needs to be clocked fairly low to avoid the hood however. But even once you fix your current wastegate interference, you still might find you have poor boost control.

My experience with the Kingugawa actuators. Other parts from them seem good.

Similarly... the fancy piston type blow-off valves, like Forge, require cleaning and re-lubing to function well. The basic diaphragm parts for VW / Porsche / Audi are less expensive, work very well, and last with no maintenance. Like this one. Off topic, but related.

OP: Small hammer blow to the brace?

DNM

I've been getting pretty full catch can contents after a few hundred miles of spirited driving. Few local boosted guys said I need to port the valve cover to allow for "lower air velocity" which will carry less oil over into the can. Truth to this? I've seen some threads on it but it seems like a need at much higher HP levels. Does one need the PCV if there's a VTA setup on the catch can? I don't see the use if both lines are just going to the same place. Deleting and tapping for AN would give a lot more flow in both "in and out" breathing. I guess keeping it would ensure engine case vacuum, would could be good?

I've had such shit luck in the past welding cast iron, myself or reputable shops. I'll definitely keep this noted though, and go this direction if I can't get good control. Other post cautioning the fancy wastegate makes me not want to start spending money where it doesn't need to be spent, so this looks like a good option in the end.

Interesting stuff, thanks for sharing. Looking at a few options for actuators, might even just try to make a new bracket for the existing one and push it down a cm or so.

I'm afraid to hammer that brace, that it might put a dent on the exterior of the hood. The brace is already pretty dinged up inside from impacts, but trying to keep the hood modification to a minimum. How hard are those braces to deform?

FWIW I've had a kingugawa actuator on my gt2860RS for ~15k miles, countless track days, dyno days, etc. and have had no issues. Though mine isn't mounted at an angle like DNM and slasers are. Maybe that's part of it.

Certainly, if mine was a perfect pull it would have been fine. With the offset jog in the arm, I’m not sure is a perfect pill is possible.

DNM